Where the truck is designed to be operated manually (not for the maintenance mode defined in 4.9.4), a manual mode shall be fitted. This manual mode shall comply with the general functional principle for manual controls as defined in ISO 3691-1:2011, 4.4; ISO 3691-2:2016, 4.4; ISO 3691-6:2013, 4.4 or with all the following requirements: